On July 1, Thomas B. Passin writes:
> I see, I couldn't be sure from your post. I don't think it changes
> the argument, though, to have the primary key equal the set of all
> columns in a table (or equvalently, all properties in the
> relationship), as long as which properties are allowed is
> unchangable. Seth was showing templates for n-ary relationships,
> and for templates to work with RDF there has to be some predicate
> that connects a template to its instance. RDF cannot (of course)
> express the semantics of that connection.
That's my point. Although it does it to reify binary relations, it is
unable to talk of relations of arity greater than two.
Note that it wouldn't be difficult to extend RDF to handle them, by
still maintaining tractability. I suspect this extension will push RDF
beyond the intentions of its creators and prophets, though :-)
cheers
-- e.
Enrico Franconi - franconi@cs.man.ac.uk
University of Manchester - http://www.cs.man.ac.uk/~franconi/
Department of Computer Science - Phone: +44 (161) 275 6170
Manchester M13 9PL, UK - Fax: +44 (161) 275 6204